Brake-related problems account for over half of all violations that can bring a highway transport vehicle into an out-of-service state during roadside inspections. Brake problems are also a common cause of transport vehicle accidents, and have been cited as a factor in nearly 30% of all truck related accidents by the Commercial Vehicle Safety Association. For owners or operators of these vehicles, brake problems can therefore lead to costly downtime and, in the event of an accident, possible liability and insurance expenses.
In many cases, status of brake systems is assessed during roadside service inspections. For vehicles equipped with certain models of disc brakes that are not equipped with a built-in wear indicator pin, inspection of the brake system typically requires removal of the wheels and disassembly of the brake system. For vehicles equipped with certain models of disc brakes that are equipped with a built-in wear indicator pin, brake system inspection typically involves a visual or manual measurement of the length of the brake wear indicator pin protruding from the caliper housing. However, it is estimated that a large percentage of vehicles that pass this test still have other brake issues that are difficult or impossible to detect without otherwise removing the wheel and/or dismantling the brake system and that warrant an out-of-service violation.
Disc brake monitoring systems are known. For example, U.S. Pat. No. 7,322,447 to Deckhut et al. discloses a disc brake having a brake disc and a brake caliper spanning the brake disc. A brake applicator shaft is supported on the brake caliper and is arranged transversely to an axis of rotation of the brake disc. The brake applicator shaft has a rotary lever for actuating the brake applicator shaft. An adjusting device provided with a thrust spindle having an end face facing away from the brake disc is provided. Upon brake application, the brake applicator shaft transmits a brake force through the thrust spindle onto the brake disc. A monitoring device is provided that has a measuring element moveable relative to the brake caliper and resting against the end face of the thrust spindle.
In-cab vehicle monitoring systems for highway transport vehicles are also known. For example, U.S. Pat. No. 5,959,365 to Mantini et al. discloses an early warning device for tire rims and hub assemblies, comprising one or more individual axle spindle sensors, a programmable microprocessor for receiving and processing the sensor signals to detect an alarm condition, and alarm means to alert the driver of a problem with one or more of the wheels. The sensors are positioned in proximity to the axles and are capable of measuring heat, noise, vibration and/or knocking, which can be indicators of imminent detachment of the tire rim or the wheel hub assembly from the vehicle.
While vehicle disc brake monitoring systems and methods are known, improvements are desired. It is therefore an object of the present invention to provide a novel vehicle brake monitoring system and method.